Control system



H. C. KRAPF CONTROL SYSTEM I Filed July 24, 1943 March 26, I946.

vINVENTOR H610; ea GKrapf.

Patented Mar. 26, 1946 UNITED STATES PATENT OFFICE Westinghouse Electric Corporation, EastPittsp burgh, Pa., a corporation of Pennsylvania Application July 24,

1943, segia1' v'.-495,9s4 I 2 claims. (Cl. 104 -151) My invention relates, generally, to control systems and, more particularly, to systems for remotely controlling the operation of electricallypropelled vehicles.

It is frequently desirable to control the operation of an electrically-propelled car or locomotive from a control station or pulpit which is located remotely from the car and an object of my invention is to provide a simplified and improved system for remotely controlling the operation of such a vehicle.

A more specific object of my invention is to provide for remotely controlling the operation of an electrically-propelled vehicle by means of two power rails and a single control rail.

Another object of my invention is to provide for positively stopping the vehicle independently of the operator when approaching the limitsof travel.

A further object of my invention is to provide for automatically limiting the vehicle speed when it is moving into the final stop position.

Still another object of my invention is to provide for full speed operation of the vehicle in the opposite direction of travel after it has reached the limit of travel in a former direction.

A still further object of my invention is to provide for stopping the vehicle from a station other than the main control station or pulpit.

Other objects of my invention will be explained fully hereinafter or will be apparent to those skilled in the art.

In accordance with one embodiment of myinvention, the operation of an electrically propelled vehicle or car is remotely controlled from a pulpit through two power rails and a single control rail. The contactors for reversing the direction of motion are mounted on the car. Other control apparatus is mounted in the pulpit from which the car is controlled. Final stop limit switches are mounted at the extreme ends of the car travel and intermediate stop limit switches are mounted along the track v at the proper positions to cut off power and stop the car before it reaches the extreme ends of its travel. The car is operated at a reduced speed from the intermediate stop position to the final stop position. I

For a. fuller understanding of the nature and objects of my invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawing in which thesingle figure is a diagrammatic view of a control system embodying my invention.

Referring to the drawing, th system shown therein comprises a motor M, having an armature winding l6 and a field winding ii, which is utilized for propelling a vehicle or car i2, the outline of which is indicated by broken lines. The motor M'is provided with a spring applied magnetic brake which is released by the energization of a solenoid coil BM. The direction of-operation of thevehicle is controlled by reversing contactors R and F which are mounted upon the vehicle Hand are utilized for reversing the motor M.

Other apparatus for controlling the operation of the motor M is mounted in a pulpit which is located remotely'iromthe vehicle l2 and includes a line switch LS for connecting power conductors I 3 and Hi to a pair of power rails I and 2 through a controller C, an overload relay 0L havingactuating coils connected in the power conductors i3 and M, a no-voltage relay NV having actuating coil that is responsive to the voltage across the conductors I3 and I4, an auxiliaryrelay AR the function of which will be explained merc fully hereinafter, and a main switch MS which may be utilized to connect the power conductors I3 and I4 to a suitable source of powernot shown).

itsshovvn,-current-collecting devices l5 and iii areprovided on the vehicle l2 for engaging thepower rails l,and 2,'respectively. A currentcollecting device ll is also provided on the vehicle l2 for engaging acontrol rail 3 which is energized from the power conductors l3 and 14 through the controller accelerating resistorRI isprovided for controlling the voltage applied-to the motor ;M-. The controller 0 is provided with a plurality of contact segments which are utilized to'shunt the-resistor RI from the motor circuit stepby-step in a manner-well known inthe art. The operation of the reversing switches R andtF is also controlled by the control1erC. 7 In order to insure that the vehicle 12 will be brought safelyto a stop at each one of the sta tions between which it is operated, an intermediate;stop limit switch Ll and a final stop limit switch L2 are provided at one station and similar limit switches L 3and L4 are provided at the other station. Asshown, the intermediate limit switches -Ll and L3 are of a type which 45 remain in theposition to which they have been actuated untilreturned to the other position by aprojecition I9 provided on the vehicle I2 for actuating the limit switches. The switches L2 andL l arenormally retained in their closed po- 5 sitions by springs unless engaged by the projection; l9 on the vehicle l2. v l I If desired, a push-button: switch PB may be located at either one of the stations or at any other desired location. The push-button switch 5 may beso connected in the controlsystem that thevehicle cannot bev operated while the switch is'open. Thus, if the switch PB is. located at the loading station it will give the loader control over the vehicle: to. prevent itfrom being moved until the loading operation is completed, The

push-button switch will also permit stopping the car from the loading station. Once the pushbutton switch is :operated, the car cannot be moved again until the 1controller 1 C lisareturned to the OE position and then actuated to an accelerating position.

In order that the functioning of the foregoing apparatus may be more clearly understoody lthe operation of the system will ,nowbedescribed in detail. Assuming that the .car is-in the .position shown at one of the stations, Whichisicalled the loading station, and that it is desired to move-the car to the other station, which "iscalle'd the-unloading station, the main switch MS isclosedto energize the conductors l3 and I4. I

'It should be noted'that, regardless or thep'osi tion of the controller C, the *car'wilrnot move at this time,-'as the no-voltage relay NV can be ener gized'only with the controller handleinthe -o position. If thepowershouldia'il while" the *car is running, it will stop andlt cannot be started again 'untilpower returns and the "controller handle is returned to the"off position where'the nogvoltage relay'is againenergizecl.

"Upon the'closure of the main "switch MS with the controller C in'the "off" position the actu ating coil of the auxiliaryrelay 'AB is energized through a circuit which maybe 'traced irom the positive conductor 13 through "conductor 2|, a contact segment C9 on the controller Cgoonductor 22, the actuating coil oftherelay ARyconductor 2-3, contact member 24 on"the limit-switch L3 and conductor 25 tothe "negative conductor l4. -A holding circuit for the'relay established through its contact members 26 which {are closed to bridge the contact members- C9' on'the controller upon the operation of *the'relay Theoperation of the 'relay' -AR'alsoclossitscontact members 21, thereby establishing an ="energizing circuit for the'actuating coilofthe-novoltage rela NV which *extendsfromthe positive conductor 13 through-the'coilof the relay NV, conductor 28, a resistor 29, conductor 3l; the contact members 210i the rela lli' contluctor 32, the push-button switch'PB' and conductor-25 to the negative conductor;

: When the controllenC' is actuated in a "forward direction to the first position, an energizing circuit is establishedfor the'actuatin'g'coil of the switch LS. This circuit may be traced from the previously energized conductor '2I through a contact segment Cl' on the contro'ller C, conductor 33, the contact members'of the overload relay L, conductor =34, contact members '35 of the no-voltage relay NV which are bridged by the contact member 35, theactuating coil'of the line-switch LS, conductor 31, contact segment G6 on the controller C, "conductor 38, the limit switch L2, conductor *39an'd the-controller segment 08 'to'the negative conductor 25.

Aholding circuit'for the-switchIiS is "estab lished through an interlock M which is closed to bridge the controller contacts 136 upon the operation of the switch LS. At-this time the con trol'rail 3 is also 'energized'through a circuitbers LSI and thecoil :of the .overload relay oL' car.

' power rail I, conductor 45, a segment A on the controller 0, conductor 45, the contact members LSlontheswitch LS andongqtthe coils of the overload relay 0L to the negativeconductor l4.

'Upon the operation of the reversing switch F, .the motor M is energized through a circuit which may be traced from the positive conductor l3 through one of the coils of the overload relay 0L, contact members LS2 of the switch LS, conductor 541,.a contactisegmentlil on the controller C, conductor 4'9, themesistor RI, conductor 5!, a segment Al on the controller C, conductor 52, the

power rail-2,theicurrent-collecting device I 6, conductor--53, contact members Fl on the reversing switchF, conductor 54, the field'winding H, conduotor 55, contact members E2 on :the sswitch.iF, conductorfi 6,:the armature winding ill], conductor 51, the coil of theibrakemagnetiBM, conductor 44, the current-collecting device.l5,iheipower rail I, "conductor 45, the controller segmentfA, 1 conductor 46,1and' thencethroughtliecontact memto thenegativeiconductor l4. V v

' soon as the line switchLS. and lthetreversing switch'F are 'ICl'OSGd, "currenti flows in' the imotor circuit, thereby releasing ithet magnctic brakecBM and developing torque in the motorto move the As the controller :0 is, actuated notch-by.-

' notch to the fifth position the tacceleratingzree sister Rl'is shunted from the" motor .circuitistep by-step in a m'anner' vvell known in the art.

When the car passes the .limit :switch 3113 this switchis actuated to-the'zoth'er ip'ositiomfromsthat shown in the drawing, thereby opening the circuit through the contact member 24 'o'n thees'witchlL3 and deen'ergizing the auxiliary relay .LHowever, as shown, the relayri'Ri-ispfa reta'rded type and the contact nriember'sifl 'l oft-his :relay, Fwhich are in't'he circuit for the coil of the relay NVQdo not open for'a predeterminedtime interval'after the deenergization of the coil of therelay'AR; In the meantime, contact members :58L-of -tl'ieilirnit switch L3 have been i'closed, thereby establishing a circuit for'the coil. of the relayiNv through contact members 59 of thellimit'swit'ch L-fand con ducter '61. In this manner the no -voltage' relay cuit established through'the contactmembers-M on the switch Ll andcontactmembrs ta s the switch L3 is opened. As'is'hown; this circuit gextends from conductor '2l through the contact members 62 of'the switch Ll, conductor "64, con tact members-63 of the switch -I.;3,"con"ductor- B5 and the controller segment C3 to the conductor-33 andithence to'the actuatingcoil of the switch-LS through the circuit previouslytraced.

Prior to the closing of thecontact members- 53 on the-switch L3, the circuit for' the coilof the switchL'S was'maintained through a controller segment 04 whichbridges the contactgmenibers V 63. Likewise, the controller segment 'britiges the contact members fiz on the limit switch'Ll to permit acceleration of the car in the zreverse' direction. In this manner the circuit is maintained for the actuating coil of the switchLS when'the controller is actuated from position i to position 5, thereby permitting thev motor 'to be accelerated in the manner previously described. "The contact car passes this switch in a direction toward the unloading station.

As explained hereinbeiore, the opening of the normally closed contact members on the limit switch Ll deenergizes th'e no-voltage relay NV and the line switch LS. Accordingly, power is removed from the motor M and the magnetic brake BM is set to stop the car. The car cannot be moved further in the same direction until the controller is actuated to the off position when the actuating coil of the relay AR is energized in the manner hereinbefore described. The relay AR closes its contact members 21 to re-establish an energizing circuit for the relay NV, as hereinbefore explained, thereby causing the relay NV to close its contact members to establish the energizing circuit for the actuating coil of the line switch LS and reconnect the motor M to the powor source.

The controller C may now be actuated in the forward direction to the first position and the car will move at a speed corresponding to this position toward the unloading station. However, if the controller is moved past the first position, power is out 01f the motor and the car stopped, since, as explained hereinbefore, the holding circuit for the switch LS through the limit switches LI and L3 was interrupted when the car passed the switch LI. In this manner the car is moved slowly to the unloading station. When the unloading station is reached, the final stop limit switch L2 is actuated to open the circuit for the actuating coil of the switch LS. The car cannot be operated further in-this direction.

After the car is unloaded, the controller C is actuated to the first position in the reverse direction and the car is moved toward the loading station in a manner similar to that described for movement from the loading to the unloading station. The interlocking is such that the car can be accelerated to full speed in this direction independently of the position of the limit switches at the unloading station. As the loading station is approached, the intermediate stop limit switch L3 causes the car to stop in the same manner as at the unloading station and further operation is the same as when the car approached the unloading station. The limit switch L4 brings the car to a final stop at the loading station and it cannot be operated further in that direction. When the direction of operation is changed, the limit switches are returned to their normal position, thereby setting up the protective circuits which require the slow operation of the car to the "final stop.

As explained hereinbefore, the push-button switch PB may be utilized to prevent the car from being moved from the loading station until the loading operation is completed. The push-button switch will also permit stopping the car at any time during its operation. Once the push-button switch is operated the car cannot be moved again until the controller is returned to the off position and again actuated to one of the accelcrating positions. The opening of the push-button switch PB deenergizes the coil for the relay NV, thereby causing the contact member 36 of this relay to bridge contact members 61 which establishes a shunt circuit around the actuating coil or the relay NV and prevents the energizetion of this coil until the controller C has been moved to the off position to interrupt the shunt circuit around the actuating coil of the relay NV. When the controller is moved to the "01? position the relays AR and NV are energized in a manner hereinbefore explained and the motor may be accelerated in the usual manner;

From the foregoing description it is apparent that I have provided a control system which makes it possible to control remotely the operation of an electrically-propelled vehicle or car by means of two power rails and one control rail.

The car is brought to a positive stop independently of the operator prior to its movement to its final position at either one of the stations at the end of its travel. The car cannot again be started until the controller is returned to the oil position and the car is limited to slow speed operation into the final stop position. When the final limit is reached the car cannot be operated further in the same direction. Full speed operation is permitted in the opposite direction of travel after the limits in the former direction have been reached. The car can be stopped at will from a station located remotely from the main control pulpit but can be started only by the operator who is located in the main control pulpit. The car can be held in any location within the limits of its travel independently of the operator. Therefore, it is evident that the present system has numerous advantages over systems previously known in the art.

Since numerous changes may be made in the above described construction and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In a control system, in combination, a motor for propelling a vehicle between predetermined stations, means on the vehicle for reversing the motor, a manually operable controller located remotely from the vehicle for controlling the operation of said reversing means and the voltage applied to the motor, switching means actuated by the vehicle for stopping the vehicle prior to its arrival at one of said stations and control means cooperating with said controller and said switching means to prevent the application 01' full voltage to the motor while the vehicle is moving in the same direction that it was p i to the operation of said switching means.

2. In a control system, in combination, a motor for propelling a vehicle between predetermined stations, means on the vehicle for reversing the motor, a manually operable controller located remotely from the vehicle for controlling the operation of said reversing means and the voltage applied to the motor, switching means actuated by the vehicle for stopping the vehicle prior to its arrival at one of said stations and control means cooperating with said controller and said switching means to prevent the application of full voltage to the motor during movement otthe vehicle to said station after the operation of said switching means.

HERMAN C. KRAPF'. 

